Excitations of molecular switches on surfaces: Insight from first principles

By means of density-functional theory and many-body perturbation theory we investigate the interaction between molecular switches and different surfaces regarding structure, level alignment as well as optical excitations. In close collaboration with experimentalists, we address the interplay between intermolecular forces and molecule-substrate interaction, with the aim to understand the mechanisms driving the excitonic coupling of the molecules and the role of the surface in their switching behavior.